Sisomicin compounds

ABSTRACT

The invention relates to sisomicin derivatives of formula (I) and methods for their preparation. Also included in the invention are compositions containing said sisomicin derivatives and the use of said derivatives and compositions for the treatment of bacterial infections.

The present invention relates to certain new sisomicin derivatives, to aprocess for their production and to their use as medicaments.

Sisomicin is an antibacterial compound from the group comprising theaminoglycoside antibiotics. Aminoglycoside antibiotics have attainedgreat importance in combating bacterial infections. However, theappearance of resistant germs reduces their wide applicability in manycases; furthermore, side-effects such as ototoxicity and nephrotoxicitycan occur. These disadvantages can be eliminated in some cases bypreparing derivatives.

Thus, for example, 1-N-(aminoalkyloxycarbonyl)-sisomicin derivativeswhich are distinguished by a high activity against sisomicin-resistantgerms have been disclosed in German Published Specification No.2,753,769 corresponding to U.S. Ser. No. 960,205, now U.S. Pat. No.4,234,572 issued Nov. 18, 1980.

In an unobvious development of the technical teaching of DE-OS (GermanPublished Specification) No. 2,753,769, the compounds according to theinvention, which are antibiotically particularly active, have now beenfound.

According to the present invention there are provided compounds whichare sisomicin derivatives of the formula ##STR1## or a salt thereof,wherein R₁ denotes a radical of the general formula --A--XH, in which

A represents an optionally branched alkylene or alkenylene radical whichhas 3 to 7, preferably 4 to 6 carbon atoms and which is substituted by 2to 4 hydroxyl groups, and

X represents oxygen or, preferably, a group of the general formula --NR₂--,

in which

R₂ represents a hydrogen atom, an alkyl or hydroxyalkyl group having 1to 6, preferably 2 to 4, carbon atoms, or an aralkyl group having 7 to10 carbon atoms (especially a mono- or bi-cyclic carbocyclic aryl --C₁--C₂ --alkyl group), preferably a benzyl radical.

The compounds according to the invention are distinguished in comparisonto the hitherto known 1-N-(aminoalkyloxycarbonyl)-sisomicin derivativesby a substantially improved tolerance, without the high antibioticactivity being restricted. The new compounds thus represent anenrichment of pharmacy.

Among the new sisomicin derivative salts of the invention, those saltsthat are pharmaceutically acceptable said addition salts areparticularly important and are preferred.

The new free sisomicin derivatives of the formula (I) and their saltscan be interconverted in any suitable manner; methods for suchinterconversion are known in the art.

The pharmaceutically useful salts are derived, in particular, frominorganic or organic acids (such as sulphuric acid, phosphoric acid,nitric acid, hydrochloric acid, hydrobromic acid, acetic acid, propionicacid, ascorbic acid and citric acid).

Straight-chain or branched polyhydroxyalkyl radicals andpolyhydroxyalkylamino radicals, such as 2,3,4-trihydroxybutyl,4-amino-2,3-dihydroxybutyl, 4-benzylamino-2,3-dihydroxybutyl,4-(2,3-dihydroxypropylamino)-2,3-dihydroxybutyl,4-dimethylamino-2,3-dihydroxybutyl, 3-amino-2,4-dihydroxybutyl,2-amino-3,4-dihydroxybutyl, 2,3,4,5-tetrahydroxypentyl,5-amino-2,3,4-trihydroxypentyl, 5-amino-2,3-dihydroxypentyl,2,3,4,5,6-pentahydroxyhexyl, 6-amino-2,3,4,5-tetrahydroxyhexyl,6-amino-4,5-dihydroxyhexyl, 1,4-dihydroxy-3-amino-but-2-yl,1,4-dihydroxy-3-methylamio-but-2-yl,1,4-dihydroxy-3-propylamino-but-2-yl,1,4-dihydroxy-3-butyl-amino-but-2-yl,1,4-dihydroxy-3-benzylamino-but-2-yl,1,4-dihydroxy-3-(2-hydroxyethylamino)-but-2-yl,2-amino-3-hydroxy-2-hydroxymethyl-propyl,3-amino-2,2-bis-(hydroxymethyl)-propyl and4-amino-2,3-bis-(hydroxymethyl)-butyl, are examples of suitable radicalsR₁.

Particularly preferred radicals R₁ are those of the formulae ##STR2##

The radicals listed above are to be understood as being merelyexemplary. They contain, as a rule, chiral C atoms, and are present asoptically pure diastereomers or diastereomer mixtures. It can beadvantageous to use the compounds according to the invention asoptically pure products.

According to the present invention there is further provided a processfor the production of a compound of the present invention in which acompound of the formula ##STR3## wherein R₃, R₄ and R₅ represent--CO--R₇ or --S--R₈, and

R₆ represents --S--R₈,

in which

R₇ denotes a radical of the formulae --CHal₃, --(CH₂)_(n).sbsb.1 --B,--O--E, ##STR4## B and D denote a hydrogen atom or an optionallysubstituted phenyl radical,

E denotes an optionally substituted phenyl radical, n₁, n₂, n₃ and n₄are, independently, 0, 1, 2, 3, 4 or 5,

Hal denotes a fluorine, chlorine or bromine atom, and

R₈ denotes an optionally substituted phenyl, diphenylmethyl ortriphenylmethyl radical,

is reacted with an acylating agent of the formula

    G-CO-O-R'                                                  (III)

wherein

G represents a leaving group (preferably a halogen atom, such as achlorine or bromine atom or an azido or optionally substituted phenoxyradical, or a radical of the formula ##STR5## and R' represents aradical R₁, as defined above, in which amino groups, if present, areprotected by amino-protective groups (such as --CO--R₇ or --S--R₈), andhydroxyl groups are protected by hydroxyl-protective groups (such as thetrityl group or the tetrahydropyranyl radical) or by alkylidene groups(such as isopropylidene, isobutylidene, cyclohexylidene or benzylidene),which simultaneously block two hydroxyl groups, and the protectivegroups R₃, R₄, R₅ and R₆, and, if appropriate, tetrahydropyranylradicals or alkylidene groups are then split off,

and the resulting compound is converted, if desired, into a saltthereof.

Preferred optionally substituted phenoxy groups of radical G are4-nitrophenoxy, phenoxy and 2,4,5-trichlorophenoxy.

1 to 3 substituents selected from trifluoromethyl, nitro, C₁ to C₄alkyl, C₁ to C₄ alkoxy, (C₁ to C₄ alkoxy)-carbonyl and phenyl, or 1 to 5halogen atoms (preferably chlorine atoms) are, for example, suitablesubstituents of the optionally substituted phenyl, diphenylmethyl ortriphenylmethyl radicals of R₈. o-Nitrophenylsulphenyl and2,3,5-trichlorophenylsulphenyl may be mentioned as examples of --SR₈groups.

1 or 2 substituents selected from nitro, halogen (preferably chlorine),C₁ to C₄ alkyl, C₁ to C₄ alkoxy and phenyl are suitable substituents ofthe optionally substituted phenyl radicals of B, D and E.

The following compounds are preferably used as starting materials of theformula (II): 2',3,3",6'-tetra-N-(o-nitrophenylsulphenyl)-sisomicin,3"-N-(o-nitrophenylsulphenyl)-2',3,6'-tris-N-trichloroacetyl-sisomicin,3"-N-(o-nitrophenylsulphenyl)-2',3,6'-tris-N-trifluoroacetyl-sisomicin,3"-N-(o-nitrophenylsulphenyl)-2',3,6'-tris-N-(2,2,2-trichloroethoxycarbonyl)-sisomicin,3"-N-(o-nitrophenylsulphenyl)-2',3,6'-tris-N-(1,1-dimethyl-2,2,2-trichloroethoxycarbonyl)-sisomicin,3"-N-(o-nitrophenylsulphenyl)-2',3,6'-tris-N-(4-methoxybenzyloxycarbonyl)-sisomicin,3"-N-(o-nitrophenylsulphenyl)-2',3,6'-tris-N-phenoxycarbonylsisomicinand3"-N-(o-nitrophenylsulphenyl)-2',3,6'-tris-N-(tert.-butoxycarbonyl)-sisomicin.The preparation of these starting materials is effected according to theprocesses described in DE-OS (German Published Specification) No.2,726,197 corresponding to U.S. Ser. No. 913,135, now U.S. Pat. No.4,190,722, issued Feb. 26, 1980 or DE-OS (German PublishedSpecification) No. 2,840,907 corresponding to U.S. Ser. No. 74,047 nowU.S. Pat. No. 4,294,959, issued Oct. 13, 1981:

The compounds of the formula (III) which are used as acylating agentscan be prepared by various processes which are in themselves known,using a suitable protective group technique:

(a) The hydroxyl groups in a polyhydroxyalkyldicarboxylic acid estersuch as diethyl mucate (1) (J. Org. Chem. 18, 952 [1953]) in equation(a), are reversibly blocked by reaction with an acetalising reagent, andthe ester groupings are then reduced to free primary hydroxyl groups,using a reducing agent, such as lithium aluminum hydride.

One of the free hydroxyl groups is converted, using a sulphonic acidchloride in pyridine, into the sulphonic acid ester, which can beconverted into an azide by a nucleophilic substitution reaction. Thesubsequent reduction yields an amino compound (for example the compoundindicated as "(5)" in the equations which follow), which is convertedinto a reactive carbonate, after blocking the amino function with aprotective group.

In following Equation (a), a reaction sequence is presented by way ofexample for diethyl mucate (the compound "(1)"), which leads to theactivated carbonate (the compound "(6)"). It can also be carried out inan analogous manner using other saccharic acid esters,bishydroxymethylamalonic acid esters, and L--, D--, DL and mesotartaricacid esters. It is also indicated in Equation (a) that a substitutedbenzylamine is obtained, for example, by reaction of the sulphonic acidester (the compound "(6)") with benzylamine, or by a reductivealkylation of the amine (the compound "(5)") with benzaldehyde, thesubstituted benzylamine yielding the activated carbonate (the compound"(7)") after reaction with 2-nitrophenylsulphenyl chloride and4-nitrophenyl chlorocarbonate. Other amines or aldehydes can also beemployed, instead of benzylamine or benzaldehyde, for this substitutionreaction.

(Comment:

The following abbreviations are used in the structural formulae belowand in the structural formulae in the Examples: ##STR6##

(b) By reaction of a polyhydroxyepoxide, the hydroxyl groups of whichare reversibly blocked, with ammonia or an amino compound, ahydroxyamino compound is obtained, which, after the introduction of aprotective group for amino and conversion of the free hydroxyl groupinto a reactive carbonate, is reacted to give the desired acylatingagent (III).

In Equation (b) a reaction sequence using4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0]octane (the compound "(8)") (J.Org. Chem. 41, 2471 [1976]) as the starting compound is presented by wayof example. ##STR7##

(c) In a polyhydroxyamino compound, the amino group is acylated, and allbut one of the hydroxyl groups are then reversibly blocked. After theN-acyl protective group has been exchanged for aN-(2-nitrophenylsulphenyl) protective group, the free hydroxyl group isconverted into a reactive carbonate.

Equation (c) shows the reactions, by way of example, using2-amino-2-hydroxymethyl-1,3-propanediol as the starting compound.##STR8##

(d) All but one of the hydroxyl groups in polyhydroxy compounds arereversibly blocked by acetalisation, and the remaining free hydroxylgroup is reacted to give a reactive carbonate.

In Equation (d) the reaction of 2,3,-4,5-dibenzylidene-xylitol (thecompound "(15)") with4,6-diphenylthieno-[3,4-d][1,3]dioxol-2-on-5,5-dioxide (the compound"(16)") (Angew. Chem. 88 480 [1976]) to give the activated carbonate(the compound "(17)") is presented by way of example. ##STR9##

In addition to the compounds "(6)", "(7)", "(11)", "(14)" and "(17)"mentioned in Equations (a) to (d), the following compounds are examplesof further suitable acylating agents of formula (III): ##STR10##

In the preparation of the compounds according to the invention, 1 mol ofthe compound of the formula (II) is generally reacted with 1 to 3 mol,preferably 1.1 to 1.5 mol, of a compound of the formula (III).

Any of the inert organic solvents, such as toluene, chloroform,methylene chloride, dimethylformamide, dimethylacetamide,dimethylsulphoxide, ethers (such as diethyl ether, dioxane andtetrahydrofuran), pyridine, and alcohols (such as methanol and ethanol)and mixtures thereof, are suitable diluents.

If acid-binding agents are necessary, any of the customary organic andinorganic acid-binding agents can be used. These preferably includealkali metal hydroxides and alkaline earth metal hydroxides (such assodium hydroxide, potassium hydroxide or calcium hydroxide), alkalimetal carbonates, alkaline earth metal carbonates, alkali metalbicarbonates and alkaline earth metal bicarbonates (such as sodiumcarbonate, potassium carbonate, sodium bicarbonate and calciumcarbonate), calcium oxide, tertiary aliphatic and aromatic amines (suchas triethylamine and N,N-dimethylaniline) and heterocyclic bases (suchas pyridine and quinoline).

The reaction temperatures can be varied within a wide range. In general,the reaction is carried out at a temperature from -30° C. to +80° C.,preferably between 0° C. and +40° C.

The reaction can be carried out under normal pressure and also atelevated pressure. It is carried out, in general, under normal pressure.

After the reaction of the compounds of formula (II) with the compoundsof formula (III) has ended, the protective groups contained in themolecule are removed.

The cleavage of the sulphenyl protective groups can be effected withweak acids or with sulphur-containing, nucleophilic reagents, such as,for example, H₂ S, thiophenol or 2-mercaptobenzthiazole, and thecleavage of the remaining protective groups can be effected with aqueousalkali metal hydroxide or alkaline earth metal hydroxide, or with acidssuch as trifluoroacetic acid, perchloric acid or boron trifluorideetherate.

If 3,2',6',3"-tetra-N-(o-nitrophenylsulphenyl)-sisomicin (the compound"(30)") and a compound "(6)" (as defined in Equation (a)) are used asstarting materials, the course of the reaction can be represented by thefollowing equation. ##STR11##

The following may be mentioned as examples of the active compoundsaccording to the invention:

1-N-[(S,S)-, 1-N-[(R,R)-, 1-N-[(R,S)- and1-N-[(S,R)-4-amino-2,3-dihydroxybutyloxycarbonyl]-sisomicin,1-N-(3-amino-2,4-dihydroxybutyloxycarbonyl)-sisomicin,1-N-(2-amino-3,4-dihydroxybutyloxycarbonyl)-sisomicin, 1-N-[(S,R)-,1-N-[(R,S)-, 1-N-[(R,R)- and1-N-[(S,S)-2,3,4-trihydroxybutyloxycarbonyl]-sisomicin,1-N-(3-amino-1,4-dihydroxybut-2-yloxycarbonyl)-sisomicin,1-N-(3-methylamino-1,4-dihydroxybut-2-yloxycarbonyl)-sisomicin,1-N-(3-propylamino-1,4-dihydroxybut-2-yloxycarbonyl)-sisomicin,1-N-(3-benzylamino-1,4-dihydroxybut-2-yloxycarbonyl)-sisomicin,1-N-[3-(2-hydroxyethylamino)-1,4-dihydroxybut-2-yloxycarbonyl]-sisomicin,1-N-[2-amino-2,2-bis-(hydroxymethyl)-ethyloxycarbonyl]-sisomicin,1-N-[(S,S,R)-, 1-N-[(R,R,S)-, 1-N-[(R,S,R)-, 1-N-[(S,R,S)-,1-N-[(S,R,R)-, 1-N-[(R,S,S)-, 1-N-[(R,R,R)- and1-N[(S,S,S)-2,3,4,5-tetrahydroxypentyloxycarbonyl)]-sisomicin,1-N-(5-amino-2,3,4-trihydroxypentyloxycarbonyl)-sisomicin,1-N-[3-amino-2,2-bis-(hydroxymethyl)-propyloxycarbonyl]-sisomicin,1-N-(2,3,4,5,6-pentahydroxyhexyloxycarbonyl)-sisomicin and1-N-(6-amino-2,3,4,5-tetrahydroxyhexyloxycarbonyl)-sisomicin.

The compounds according to the invention are antimicrobial agents with awide spectrum of action and with particular activity againstgram-negative bacteria. These properties make it possible to use them asmedicaments, particularly in combating the illnesses which are producedby bacteria and which occur in warm-blooded animals. They areparticularly suitable for the prophylaxis and chemotherapy of local andsystemic infections, particularly infections of the urogenital system,which are caused by gram-negative bacteria, for example E. coli,Proteus, Klebsiella and Pseudomonas, in medicine. Inhibitory areolae inthe agar hole test were found, for example, against the followingstrains of bacteria in a concentration of 100 micrograms/1 ml:

Pseudomonas aerug. 5737,

Pseudomonas aerug. F 41,

Klebsiella pneum. 2 Munich,

Klebsiella pneum.

1 Dusseldorf,

E. coli Munster, and

E. coli Neumann.

As stated above, the invention also relates to the use in medicine ofthe compounds of the invention.

The present invention provides a pharmaceutical composition containingas active ingredient a compound of the invention in admixture with aninert pharmaceutical carrier, e.g. a solid or liquefied gaseous diluent,or in admixture with a liquid diluent other than a solvent of amolecular weight less than 200 (preferably less than 350) except in thepresence of a surface active agent.

The invention further provides a pharmaceutical composition containingas active ingredient a compound of the invention in the form of asterile and/or physiologically isotonic aqueous solution.

The invention also provides a medicament in dosage unit form comprisinga compound of the invention.

The invention also provides a medicament in the form of tablets(including lozenges and granules), dragees, capsules, pills, ampoules orsuppositories comprising a compound of the invention.

"Medicament" as used in this Specification means physically discretecoherent portions suitable for medical administration. "Medicament indosage unit form" as used in this Specification means physicallydiscrete coherent units suitable for medical administration eachcontaining a daily dose or a multiple (up to four times) or submultiple(down to a fortieth) of a daily dose of the compound of the invention inassociation with a carrier and/or enclosed within an envelope. Whetherthe medicament contains a daily dose or, for example, a half, a third ora quarter of a daily dose will depend on whether the medicament is to beadministered once or, for example, twice, three times or four times aday respectively.

The pharmaceutical composition according to the invention may, forexample, take the form of ointments, gels, pastes, creams, sprays(including aerosols), lotions, suspensions, solutions and emulsions ofthe active ingredient in aqueous or non-aqueous diluents, syrups,granulates or powders.

The diluents to be used in pharmaceutical compositions (e.g. granulates)adapted to be formed into tablets, dragees, capsules and pills includethe following: (a) fillers and extenders, e.g. starch, sugars, mannitol,and silicic acid; (b) binding agents, e.g. carboxymethyl cellulose andother cellulose derivatives, alginates, gelatine and polyvinylpyrrolidone; (c) moisturizing agents, e.g. glycerol; (d) disintegratingagents, e.g. agar-agar, calcium carbonate and sodium bicarbonate; (e)agents for retarding dissolution e.g. paraffin; (f) resorptionaccelerators, e.g. quaternary ammonium compounds; (g) surface activeagents, e.g. cetyl alcohol, glycerol monostearate; (h) adsorptivecarriers, e.g. kaolin and bentonite; (i) lubricants, e.g. talc, calciumand magnesium stearate and solid polyethyl glycols.

The tablets, dragees, capsules and pills formed from the pharmaceuticalcompositions of the invention can have the customary coatings, envelopesand protective matrices, which may contain opacifiers. They can be soconstituted that they release the active ingredient only or preferablyin a particular part of the intestinal tract, possibly over a period oftime. The coatings, envelopes and protective matrices may be made, forexample, of polymeric substances or waxes.

The ingredient can also be made up in microencapsulated form togetherwith one or several of the above-mentioned diluents.

The diluents to be used in pharmaceutical compositions adapted to beformed into suppositories can, for example, be the usual water-solublediluents, such as polyethylene glycols and fats (e.g. cocoa oil and highesters (e.g. C₁₄ -alcohol with C₁₆ -fatty acid)) or mixtures of thesediluents.

The pharmaceutical compositions which are ointments, pastes, creams andgels can, for example, contain the usual diluents, e.g. animal andvegetable fats, waxes, paraffins, starch, tragacanth, cellulosederivatives, polyethylene glycols, silicones, bentonites, silicic acid,talc and zinc oxide or mixtures of these substances.

The pharmaceutical compositions which are powders and sprays can, forexample, contain the usual diluents, e.g. lactose, talc, silicic acid,aluminium hydroxide, calcium silicate, and polyamide powder or mixturesof these substances. Aerosol sprays can, for example, contain the usualpropellants, e.g. chlorofluorohydrocarbons.

The pharmaceutical compositions which are solutions and emulsions can,for example, contain the customary diluents (with, of course, theabove-mentioned exclusion of solvents having a molecular weight below200 except in the presence of a surface-active agent), such as solvents,dissolving agents and emulsifiers; specific examples of such diluentsare water, ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethylacetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butyleneglycol, dimethylformamide, oils (for example ground nut oil), glycerol,tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid estersof sorbitol or mixtures thereof.

For parenteral administration, solutions and emulsions should besterile, and, if appropriate, blood-isotonic.

The pharmaceutical compositions which are suspensions can contain theusual diluents, such as liquid diluents, e.g. water, ethyl alcohol,propylene glycol, surface-active agents (e.g. ethoxylated isostearylalcohols, polyoxyethylene sorbite and sorbitane esters),microcrystalline cellulose, aluminium metahydroxide, bentonite,agar-agar and tragacanth or mixtures thereof.

All the pharmaceutical compositions according to the invention can alsocontain colouring agents and preservatives as well as perfumes andflavouring additions (e.g. peppermint oil and eucalyptus oil) andsweetening agents (e.g. saccharin).

In addition to a compound of the invention, the pharmaceuticalcompositions and medicaments according to the invention can also containother pharmaceutically active compounds. They may also contain aplurality of compounds of the invention.

Any diluent in the medicaments of the present invention may be any ofthose mentioned above in relation to the pharmaceutical compositions ofthe present invention. Such medicaments may include solvents ofmolecular weight less than 200 as sole diluent.

The discrete coherent portions constituting the medicament according tothe invention will generally be adapted by virtue of their shape orpackaging for medical administration and may be, for example, any of thefollowing: tablets (including lozenges and granulates), pills, dragees,capsules, suppositories and ampoules. Some of these forms may be made upfor delayed release of the active ingredient. Some, such as capsules,include a protective envelope which renders the portions of themedicament physically discrete and coherent.

The production of the above-mentioned pharmaceutical compositions andmedicaments is carried out by any method known in the art, for example,by mixing the active ingredient(s) with the diluent(s) to form apharmaceutical composition (e.g. a granulate) and then forming thecomposition into the medicament (e.g. tablets).

This invention further provides a method of combating theabove-mentioned diseases in warm-blooded animals, preferably humans,which comprises administering to the animals a compound of the inventionalone or in admixture with a diluent or in the form of a medicamentaccording to the invention. The dosage of the compounds according to theinvention is usually similar to the dosage of the 1-N-unsubstitutedcompound. The dosage range in humans is generally from 0,3 mg to 30 mgper kg per day, preferably 1,5 to 7,5 mg per kg per day. Nevertheless,it can at times be necessary to deviate from those dosage rates, and inparticular to do so as a function of the nature and body weight of thesubject to be treated, the individual reaction of this subject to thetreatment, the type of formulation in which the active ingredient isadministered and the mode in which the administration is carried out,and the point in the progress of the disease or interval at which it isto be administered. Thus it may in some case suffice to use less thanthe above-mentioned minimum dosage rate, whilst other cases the upperlimit mentioned must be exceeded to achieve the desired results. Wherelarger amounts are administered it can be advisable to divide these intoseveral individual administrations over the course of the day.

The compounds of the invention can be administered orally with theadministration being effected in a single administration or distributedover several administrations and the compounds can also be administeredtopically.

In general, topical preparations contain approximately 0.1 toapproximately 3.0 g of the compounds of the invention per 100 g ofointment, cream or lotion. The topical administration is effectedapproximately 2 to 5 times per day.

The pharmaceutical compositions according to the invention can occur inliquid form as solutions or suspensions for use in ears and eyes or forparenteral administration in the form of intramuscular or intravenousinjections. Injection solutions or injection suspensions are usuallyadministered so that approximately 1 to 15 mg of active compound perkilogram of body weight enter the infected organism in 2 to 4 doses perday.

For use in veterinary medicine the active compound can be mixed withanimal feedstuffs. The present invention therefore also provides amedicated feed comprising the active compound of the present inventionin admixture with a nutritious material.

The Examples which follow illustrate the preparation of the compoundsaccording to the invention. If not otherwise indicated, data forquantities are to be understood as meaning parts by weight or percent byweight. Except as otherwise indicated, the compound numbers given inbrackets in the Examples refer to the compounds previously indicated inthe Equations (a) to (d) and the following formulae.

The following eluant systems were used for the chromatographicseparations in the embodiment examples:

A. Toluene/ethyl acetate (2:1).

B. Methylene chloride/methanol (95:5).

C. Methylene chloride/methanol/20% aqueous ammonia (2:4:1).

D. Methylene chloride/methanol/17% aqueous ammonia (150:20:1).

The analytical separations were carried out over silica gel instant thinlayer chromatography plates (Merck, Darmstadt), and the preparativeseparations using silica gel 60 (Merck, Darmstadt).

EXAMPLE 1 1-N-([S,S]-4-Amino-2,3-dihydroxy-butyloxycarbonyl)-sisomicin##STR12##

(a) Preparation of the compounds (34) and (35)

190.5 g of p-toluenesulphonic acid chloride (1 mol) were added inportions to a solution of 162 g (1 mol) of(+)-trans-4,5-bis[hydroxymethyl]-2,2-dimethyl-1,3-dioxolane (seeSynthesis 1979, 350) in 600 ml of pyridine at -15° C., and the mixturewas stirred until it was homogeneous. The mixture was kept at -25°overnight, concentrated in a high vacuum, stirred with system A, andfiltered off from undissolved material. The mother liquor was subjectedto chromatography over 1.4 kg of silica gel (system A) to separate thecompounds (34) and (35).

Yield: Compound (34): 176 g of colourless oil (55.7%); Rf value (systemA): 0.29; NMR: 1 tosyl radical Compound (35): 53 g of white crystals(11.3%); melting point 88°-91°; Rf value (system A): 0.78, NMR: 2 tosylradicals.

(b) Preparation of compound (36)

A mixture of 162 g of compound (34) (0.51 mol) in 750 ml ofdimethylformamide and 77 g of NaN₃ (1.18 mol) in 77 ml of water washeated under reflux for 1/2 a day and was concentrated in a high vacuum,stirred with a little of system A and filtered from the precipitate, andthe mother liquor was filtered over 150 g of silica gel (eluant: systemA).

Yield: 68.9 g (72%) of oil; IR: 2090/cm; Rf value (system A): 0.14.

(c) Preparation of compound (37)

63.9 g of compound (36) (0.34 mol) in 500 ml of ethyl acetate werehydrogenated during the course of 3 days using 4 g of Raney Ni, whilsthydrogen was passed through the mixture, and the reaction was monitoredby means of thin layer chromatography (system A). The mixture wasfiltered off from the catalyst, and the filtrate was concentrated invacuo.

Yield: 50 g (91%) of colourless oil; Rf value (system D): 0.29.

(d) Preparation of compound (38)

A solution of 59 g of 2-nitrophenylsulphenyl chloride (NPS-Cl) (0.21mol)/300 ml of dioxan and 150 ml of 2 N NaOH were simultaneously addeddropwise to a solution of 50 g of compound (37) (0.31 mol) in 300 ml ofdioxan/156 ml of 2 N NaOH at pH>8, and the mixture was stirred for 2hours at room temperature. The mixture was concentrated in vacuo, theresidue was dissolved in 300 ml of methylene chloride, and 100 ml ofwater were added to the solution. The aqueous phase which had beenseparated off was extracted with twice 50 ml of methylene chloride, andthe combined organic phases were washed with a total of 100 ml of water,dried with Na₂ SO₄, concentrated in vacuo and filtered over 200 g ofsilica gel (eluant: system A).

Yield: 76 g (78%) of orange oil; Rf value (system A): 0.25.

(e) Preparation of compound (18)

48.8 g of p-nitrophenylchloroformate (0.24 mol) were added to a solutionof 76 g of compound (38) (0.24 mol) in 450 ml of pyridine, and themixture was stirred overnight at room temperature. When compound (38)could no longer be detected by means of thin layer chromatography, themixture was concentrated in a high vacuum, and the residue was taken upin 200 ml of methylene chloride, washed with 3 times 75 ml of water anddried with Na₂ SO₄. The solution was concentrated and was purifiedchromatographically (system A) over 300 g of silica gel. Yield: 81 g oforange oil; thin layer chromatography (system A): 1 principal component(Rf value 0.64), 1 minor component (Rf value 0.50) (identical withp-nitrophenol).

(f) Preparation of compound (39)

17.6 g of compound (18) (3.6×10⁻² mol) in 20 ml of methylene chloridewere added to a solution of 33 g (3×10⁻² mol) of3,2',6',3"-tetra-N-(o-nitrophenylsulphenyl)-sisomicin (compound (30))(see German Published Specification No. 2,726,197) in 160 ml ofpyridine, and the mixture was stirred for 1 day at room temperature. Themixture was concentrated in a high vacuum, and the intermediate productof the acylation was isolated by means of chromatography over 800 g ofsilica gel (system B; Rf value: 0.45): 39.5 g of an orange solid product(as a solidified foam). Cleavage of the NPS groups was effected bydissolving the product in 70 ml of methylene chloride, adding a solutionof 85 g of 2-mercaptobenzthiazole in 300 ml of methanol/50 ml ofmethylene chloride, and acidifying the mixture with 15 ml ofconcentrated HCl. The mixture was extracted with twice 100 ml of water,the aqueous phase was washed with 3 times 50 ml of methylene chloride,and the acid aqueous solution was evaporated to 100 ml and was left tostand for 7 days at room temperature to split off the isopropylideneprotective group. The solution was thereafter rendered alkaline with acommercial ion exchanger, and was concentrated and subjected tochromatography over 200 g of silica gel. The following fractions wereisolated:

I. 3.5 g, thin layer chromatography (system C): 1 principal component(Rf value 0.13), 1 minor component (Rf value 0.24)=sisomicin.

II. 6.9 g,thin layer chromatography (system C): 1 principal product (Rfvalue 0.13),

III 0.4 g,thin layer chromatography (system C): 1 principal product (Rfvalue 0.13), 1 trace (Rf value 0.08)

The fraction II contained the pure compound (39); in the fractions I andIII, impurities were also present in addition to compound (39), theimpurities being removed by a repeated chromatography.

EXAMPLE 2 1-N-([R,R]-4-Amino-2,3-dihydroxy-butyloxycarbonyl)-sisomicin##STR13##

The preparation was effected analogously to Example 1, using(-)-trans-4,5-bis[hydroxymethyl]-2,2-dimethyl-1,3-dioxolan as thestarting material, which was prepared from diethyl D(-)-tartrate,corresponding to compound (33), according to B. A. Murrer et al.,Synthesis 1979, 350. The R_(f) values of all the intermediate productswere indentical with those of the corresponding isomers which are listedin Example 1. The ¹³ C-NMR spectrum of compound (40) is recorded inTable 1:

                  TABLE 1                                                         ______________________________________                                        .sup.13 C shifts δ (ppm, relative to TMS = 0) for (40) in D.sub.2       C atoms,         Signal     Relative                                          i.e. assignment  positions  intensities                                       ______________________________________                                        C-1"             100.441    3.772                                             C-2"             70.962     3.052                                             C-3"             64.239     3.193                                             C-4"             72.824     3.795                                             C-5"             69.390     2.429                                             N--CH.sub.3 at C-3"                                                                            37.456     3.689                                             CH.sub.3 at C-4" 22.388     4.200                                             C-1              52.139     2.080                                             C-2              32.225     2.101                                             C-3              49.748     5.319                                             C-4              81.618     1.736                                             C-5              75.584     3.678                                             C-6              84.105     2.072                                             C-1'             99.719     2.244                                             C-2'             47.229     4.758                                             C-3'             25.453     3.159                                             C-4'             98.836     3.621                                             C-5'             147.715    1.364                                             C-6'             43.362     2.885                                             NH--CO--O-- of the radical                                                    at 1-N           158.483    1.308                                             --OCH.sub.2 of the radical at 1-N                                                              66.790     1.528                                             --CH.sub.2 --NH.sub.2 of the radical                                          at 1-N           42.752     4.055                                             --CH(OH)--CH(OH)-- of the                                                                      71.332 and 1.899 and 3.281                                   radical at 1-N   68.427                                                       ______________________________________                                    

EXAMPLE 31-N-([R,S,R,S]-6-Amino-2,3,4,5-tetrahydroxy-hexyloxycarbonyl)-sisomicin##STR14##

(a) Preparation of compound (2)

36 g of diethyl mucate (the compound (1)) (see J. Org. Chem. 18, 952[1953]) were heated under reflux with 29.8 g of 2,2-dimethoxypropane(0.29 mol) and 0.3 g of p-toluenesulphonic acid in 400 ml of acetone for13 hours, and the condensate was dried over 50 g of zeolite (4 Å; driedat 100° C./12 mm). For the working-up process, 0.2 g of Na₂ CO₃ wereadded to the mixture, and it was filtered and concentrated, and theresidue was recrystallised from 50 ml of ethanol.

Yield: 25.2 g (53%); melting point 85°-87° C.

IR: 1,760/cm; NMR (CDCl₃): δ=1.3 t (2 ester-CH₃), 1.47 d(6-isopropylidene-CH₃), 4.25 q (2 ester-CH₂), 4.5 m (4 OH). R_(f) value(system A): 0.64

(b) Preparation of compound (3)

A suspension of 5.7 g of LiAlH₄ (0.15 mol) in 250 ml of absolute etherwas initially introduced at 0° C. under N₂, and a solution of 24.3 g ofcompound (2) (0.07 mol) in 400 ml of absolute ether was added dropwiseto the suspension at an internal temperature of 0°-15° C. during thecourse of 30 minutes. The suspension was then heated under reflux for 5hours, and 15 ml of water and 15 ml of 4 N NaOH were carefully added toit at -10° C. to -5° C. under N₂. The precipitate was filtered off undersuction, washed with ether and boiled for a further 3 hours with 250 mlof dioxan. The combined mother liquors were concentrated, and theresidue was recrystallised from 25 ml of isopropanol.

Yield: 6.3 g (29.4%), melting point 111°-113° C.; R_(f) value (systemA): 0.1. NMR (CDCl₃): δ=1.4 broad s (4 isopropylidene-CH₃), 2.62 s (2OH; exchange with CD₃ OD), 3.82 m (2 CH₂ -O), 4.0 m (4 CH-O).

(c) Preparation of compounds (4) and (41)

6 g of compound (3) (0.023 mol) were dissolved in 15 ml of absolutepyridine, and 4.4 g of p-toluenesulphonic acid chloride (0.023 mol) wereadded in portions to the solution at -15° C. during the course of 5minutes. The mixture was further stirred at -15° C. until it washomogeneous, and was left to stand overnight at -25° C. to -30° C. andstirred with 100 ml of water at 0° C. The precipitate which separatedout was filtered off under suction, washed with water and dried at 40°C./12 mm (7.5 g). To separate the two components, the mixture wassubjected to chromatography over 150 g of silica gel, using CH₂ Cl₂/methanol (99:1) as the eluant:

Compound (41): 2 g, melting point 164°-166° C.; R_(f) value 0.72; NMRshows 2 tosyl radicals.

Compound (4): 3.5 g, melting point 83°-84° C.; R_(f) value 0.29; NMRshows 1 tosyl radical.

(d) Preparation of compound (5)

A solution of 1.2 g of NaN₃ (1.84×10⁻² mol) in 2 ml of water were addedto 3.33 g of compound (4) (8.3×10⁻³ mol) in 15 ml of dimethylformamide,and the mixture was heated under reflux for 9 hours. The mixture wasconcentrated in vacuo, the residue was stirred with a littletoluene/ethyl acetate (2:1), the solution was filtered off from thesalt, and the filtrate was subjected to chromatography over 150 g ofsilica gel using system A as the eluant.

Yield: 1.5 g of oil (62.2%); IR: 2,100/cm; R_(f) value (system A): 0.27.

1.5 g (5.2×10⁻³ mol) of the oil thus obtained were hydrogenated at roomtemperature and under normal pressure in 80 ml of ethyl acetate, using 1g of Pt black, for 2 days, and the reaction was monitored by thin layerchromatography. The catalyst was filtered off, the filtrate wasconcentrated, and a white solid product was obtained, which, accordingto thin layer chromatography (system A), no longer contained azide.

Yield: 1.1 g (81%), melting point 130°-133° C.

(e) Preparation of compound (6)

0.91 g of compound (5) (3×10⁻³ mol) were initially introduced into 3.5ml of dioxan and 1.75 ml of 2 N NaOH, and a solution of 0.65 g of NPS-Cl(3.5×10⁻³ mol) in 3.5 ml of dioxan and 2.2 ml of 2 N NaOH weresilultaneously added dropwise at pH 8-9. After 60 minutes, a newcomponent could be detected in the thin layer chromatography (system A),and the component was obtained in pure form after evaporating thesolvent by filtration over 30 g of silica gel with system A.

Yield: 0.8 g (64%), melting point 112°-115° C.; R_(f) value (system A):0.2

NMR (CDCl₃):=1.38 2 d (4 isopropylidene-CH₃), 2.22 t broad (OH), 3.23 m(3H), 3.78 m (6H), 7.0-8.4 m (4H, NPS radical).

A solution of 750 mg (1.8×10⁻³ mol) of the product, which was obtainedin this manner, in 4 ml of absolute pyridine was stirred for 2 hours atroom temperature with 360 mg of p-nitrophenyl chloroformate (1.8×10⁻³mol), and the mixture was then concentrated in a high vacuum and waspurified chromatographically over 30 g of silica gel using system A.

Yield: 0.9 g; R_(f) value (system A): 0.54.

(f) Preparation of compound (32)

260 mg of compound (6) were added to a solution of 330 mg of3,2',6',3""-tetra-N-(o-nitrophenylsulphenyl)-sisomicin (30) (3×10⁻⁴ mol)in 1.5 ml of pyridine, and the mixture was left to stand overnight atroom temperature. After the solution had been concentrated byevaporation, the reaction product (compound (31)) was isolated over 40 gof silica gel (system B) and was cleaved analogously to Example (1 f).To split off the two isopropylidene groups, the acid aqueous solutionremained standing for 11 days at room temperature, the stepwise cleavagetaking place very slowly via a monoisopropylidene derivative (R_(f)value: 0.34; system C) to give the completely de-blocked derivative(R_(f) value: 0.02; system C). The mixture was then rendered alkalinewith a commercial ion exchanger, was concentrated, and was purified bysubjecting it to chromatography over 5 g of silica gel using system C asthe eluant.

Yield: 47 mg (24%)

R_(f) value (system C): 0.02 (for comparison: sisomicin R_(f) =0.16)

The ¹³ C spectrum of (32) is recorded in Table 2:

                  TABLE 2                                                         ______________________________________                                        .sup.13 C shifts δ (ppm, relative to TMS = 0) for (32) in D.sub.2       C atoms,         Signal           Relative                                    i.e. assignment  positions        intensities                                 ______________________________________                                        C-1"             101.271          <1                                          C-2"             70.272           2.262                                       C-3"             64.463   (see    3.330                                                                 below)                                              C-4"             72.487           3.097                                       C-5"             68.957           2.959                                       N--CH.sub.3 at C-3"                                                                            37.135           4.049                                       CH.sub.3 at C-4" 22.308           4.699                                       C-1              52.139           2.090                                       C-2              35.586           2.492                                       C-3              49.764           7.372                                       C-4              81.651           <1                                          C-5              75.584           2.961                                       C-6              83.688           1.863                                       C-1'             100.136          4.549                                       C-2'             47.133           4.413                                       C-3'             25.453           3.222                                       C-4'             99.590           2.792                                       C-5'             145.946          <1(broad)                                   C-6'             43.891           3.669                                       CO of the radical at N-1                                                                       158.579          1.907                                       CH.sub.2 NH.sub.2 of the radical at N-1                                                        42.415           4.160                                       CHOH, α to CH.sub.2 of the                                                               71.127           3.092                                       radical at N-1                                                                residual CHOH of the radical                                                                   68.3             4.936                                                                         (broadened)                                 CH.sub.2 O of the radical at N-1                                                               64.46    (see    3.330                                                                 above)                                              ______________________________________                                    

EXAMPLE 41-N-(3-Amino-2,2-bis-[hydroxymethyl]-propyloxycarbonyl)-sisomicin (51)##STR15##

(a) Preparation of compound (43)

A solution of 55.5 g of compound (42) (see J. Amer. Chem. Soc. 94, 171[1972]) (0.20 mol) in 150 ml of ether was added dropwise to a suspensionof 16.9 g of LiAlH₄ (0.45 mol) in 150 ml of ether during the course of90 minutes, and the mixture was heated under reflux for 5 hours. 20 mlof water were carefully added to the mixture at -5° C., the latter wasdiluted with 250 ml of ether and was filtered, and the residue wasrinsed with ether. The precipitate was boiled with 300 ml of dioxan for3 hours, and the combined organic phases were dried with Na₂ SO₄,filtered and concentrated. The solid residue was recrystallised from 20ml of isopropanol.

Yield: 4.6 g (12.5%), melting point 99°-100° C.

NMR: A mixture of the two conformers.

(b) Preparation of compounds (44), (45) and (46)

5 g of p-toluenesulphonic acid chloride (0.025 mol) were added inportions to 4 g of compound (43) (0.02 mol) in 12 ml of absolutepyridine at -15° C., and the mixture was stirred until it washomogeneous. The mixture was left to stand overnight at 25° C., and wasconcentrated in vacuo and subjected to chromatography over 100 g ofsilica gel with system A.

Compound (46): 0.4 g of oil; R_(f) value (system A): 0.84

Compound (44): 0.9 g white crystals; melting point 103°-106° C.; R_(f)value (system A): 0.5

Compound (45): 1.0 g of white crystals; melting point 73°-75° C.; R_(f)value (system A): 0.4

(c) Preparation of compound (47)

390 mg of NaN₃ in 0.5 ml of water were added to 0.9 g of the product ofExample (4b) (2.6×10⁻³ mol) in 3 ml of dimethylformamide, and themixture was heated under reflux for 5 hours, concentrated and filteredover 50 g of silica gel (eluant: system A).

Yield: 0.5 g of oil (89%); IR: 2,100/cm; R_(f) value (system A): 0.57.

(d) Preparation of compound (48)

0.5 g of compound (47) (2.3×10⁻³ mol) were hydrogenated in an H₂ streamin 20 ml of ethyl acetate, using 0.3 g of Pt black, during the course of6 days, and the reduction in quantity of the starting compound wasmonitored by means of thin layer chromatography (system A). After thecatalyst had been filtered off, the mixture was concentrated in vacuo.

Yield: 0.3 g (69%).

(e) Preparation of compound (49)

0.3 g of o-nitrophenylsulphenyl chloride (1.5×10⁻³ mol) in 1.5 ml ofdioxan and 0.9 ml of 2 N NaOH were added simultaneously to 0.3 g ofcompound (48) (1.58×10⁻³ mol) in 1.5 ml of dioxan and 0.75 ml of 2 NNaOH at pH >8. After 15 hours, the mixture was concentrated in vacuo,taken up in 5 ml of CH₂ Cl₂, washed with twice 3 ml of water, dried withNa₂ SO₄, concentrated and purified over 50 g of silica gel (eluant:system A).

Yield: 0.4 g (74%); R_(f) value (system A): 0.42.

(f) Preparation of compound (28)

A solution of 0.4 g of (49) (1.1×10⁻³ mol) in 2 ml of pyridine wasstirred with 0.22 g of p-nitrophenyl chloroformate (1.1×10⁻³ mol) for 5hours at room temperature, and the mixture was concentrated in a highvacuum and was subjected to chromatography over 50 g of silica gel withsystem A.

Yield: 0.3 g (54%); IR: 1,770/cm; R_(f) value (system A): 0.7.

(g) Preparation of compounds (50) and (51)

91 mg of compound (28) (1.8×10⁻⁴ mol) were added to 165 mg of3,2',6',3"-tetra-N-(o-nitrophenylsulphenyl)-sisomicin (the compound(30)) (1.5×10⁻⁴ mol) in 0.75 ml of pyridine, and the mixture was left tostand overnight at room temperature and was concentrated in a highvacuum. The reaction product was separated off over 20 g of silica gelusing system B, was taken up in 0.9 ml of CH₂ Cl₂, and, to split off theo-nitrophenylsulphenyl protective groups, a solution of 255 mg of2-mercaptobenzthiazole (1.5×10⁻³ mol) in 0.9 ml of methanol/1.5 ml ofmethylene chloride and a little concentrated hydrochloric acid wereadded, the latter until an acid reaction was obtained, and the mixturewas diluted with 1 ml of water. The acid solution remained standing for2 days at room temperature, it being intended that the isobutylidenegroup be removed from the primary cleavage product. Since, according tothin layer chromatography, the first cleavage product was still presentin an unchanged form after this period, it was isolated, for a structuredetermination, by the addition of an ion exchanger in the (OH--) form,concentration and chromatography over 5 g of silica gel (system C).

Yield: 43 mg of a colourless solid product; R_(f) value (system C): 0.62(sisomicin: R_(f) value: 0.24).

The ¹³ C-NMR (see Table 3) showed the presence of the structure ofcompound (50), and therefore of the isobutylidene group. Its cleavagewas effected by again taking up the compound in 1.2 ml of 6.5% strengthhydrochloric acid and leaving the mixture to stand for 2 days at roomtemperature. The mixture was rendered alkaline with an ion exchanger inthe (OH--) form, and was thereafter concentrated and subjected tochromatography over 5 g of silica gel (system C), compound (51) beingobtained in pure form:

Yield: 10 mg; R_(f) value (system C): 0.23 (Sisomicin: R_(f) value:0.24).

                  TABLE 3                                                         ______________________________________                                        .sup.13 C shifts δ (ppm, relative to TMS = 0) for (50) in D.sub.2       C atoms,             Signal   Relative                                        i.e. assignment      positions                                                                              intensities                                     ______________________________________                                        C-1"                 100.665  3.916                                           C-2"                 70.786   4.153                                           C-3"                 70.609   2.401                                           C-4"                 73.049   5.285                                           C-5"                 68.571   3.577                                           N--CH.sub.3 at C-3"  7.665    4.329                                           CH.sub.3 at C-4"     22.533   3.108                                           C-1                  52.027   1.978                                           C-2                  32.546   5.679                                           C-3                  49.845   4.094                                           C-4                  81.818   1.801                                           C-5                  75.552   3.809                                           C-6                  84.442   2.779                                           C-1'                 99.719   3.072                                           C-2'                 47.341   4.233                                           C-3'                 25.485   2.715                                           C-4'                 97.665   4.341                                           C-5'                 149.208  2.514                                           C-6'                 43.105   4.841                                           (CH.sub.3).sub.2 of the radical at N-1                                                             16.788   8.721                                           NH--COO of the radical at N-1                                                                      158.675  2.167                                           C-2 of the radical at N-1                                                                          106.908  4.671                                           C-4/C-6 of the radical at N-1                                                                      64.255   4.215                                           OCH.sub.2 at C-5 of the radical                                                                    69.631   2.422                                           at N-1                                                                        CH.sub.2 NH.sub.2 at C-5 of the radical                                                            42.575   3.055                                           at N-1                                                                        C-5 of the radical at N-1                                                                          38.210   5.400                                           CH of isopropyl of the                                                                             35.611   2.061                                           radical at N-1                                                                ______________________________________                                    

EXAMPLE 51-N-(2-Amino-3-hydroxy-2-hydroxymethyl-propyloxycarbonyl)sisomicin##STR16##

(a) Preparation of compound (12)

60.5 g (0.5 mol) of 2-amino-2-hydroxymethyl-1,3-propanediol were heatedunder reflux in 200 ml of methanol with 42 g of methyl formate (0.7 mol)for 4 hours. The crystals which were precipitated on cooling the mixturewere filtered off under suction and washed with methanol.

Yield: 60.8 g (91.4%), melting point 117°-118° C., IR: 1,670, 1,645/cm.

NMR (d₆ -DMSO): δ=˜3.5 2 signals (3CH₂), 4.83 s broad (3OH), 6.83 d and7.52 s broad (NH), 8.0 d and 8.2 d (CHO).

(b) Preparation of compound (13)

29.8 g of compound (12) (0.2 mol) were heated under reflux in 150 ml ofdimethylformamide with 200 ml of 2,2-dimetoxypropane and 200 mg ofp-toluenesulphonic acid for 4 hours, the mixture was cooled and waspoured into 1 liter of 0.5% NaHCO₃ solution, and the latter wasextracted with 3 times 150 ml of methylene chloride. The solution whichhad been dried with Na₂ SO₄ was concentrated, and the residual red-brownoil (3 g) was subjected to chromatography over 100 g of silica gel usingsystem D.

Yield: 2.2 g (5.5%); R_(f) value (system D): 0.8; IR: 1,670/cm.

(c) Preparation of compound (14)

3.8 g of compound (13) (0.02 mol) were heated under reflux with asolution of 10 g of Ba(OH)₂. 8H₂ O in 50 ml of water for 5 hours, themixture was concentrated, and the residue was stirred with 5 ml ofsystem D. The undissolved salts were filtered off, and the filtrate wassubjected to chromatography over 100 g of silica gel (system D):

Yield: 0.4 g (12.4%), R_(f) value (system D): 0.32.

300 mg (1.8×10⁻³ mol) of the amine thus obtained were acylated at roomtemperature in 2 ml of dioxan/1 ml of 2 N NaOH by the simultaneousdropwise addition of 355 mg of NPS-Cl (1.8×10⁻³ mol) in 2 ml of dioxanand 1.3 ml of 2 N NaOH. The product was worked up by concentration,dissolving in methylene chloride, washing with water, drying with Na₂SO₄ and chromatography (system A) over 40 g of silica gel.

Yield: 0.2 g of a yellow solid product (35%), Melting point 148°-150°C.; R_(f) value (system A): 0.15.

0.2 g (6.4×10⁻⁴ mol) of the acylated product thus obtained was reactedin 1.5 ml of pyridine with 188 mg of p-nitrophenyl chloroformate at roomtemperature for 4 hours. The mixture was concentrated, was taken up in 5ml of methylene chloride, extracted with twice 1.5 ml of water and driedwith Na₂ SO₄. The product (compound (14)) isolated after chromatographyover 40 g of silica gel (system A) also contained, in addition to theprincipal component (R_(f) value 0.48), nitrophenol and a furtherimpurity (R_(f) value 0.68), and could be directly used for furtherreaction.

IR: 1,760 cm⁻¹.

(d) Preparation of the compound (52)

165 mg of 3,2',6',3"-tetra-N-(o-nitrophenylsulphenyl)-sisomicin(compound (30)) (1.5×10⁻⁴ mol) were dissolved in 0.75 ml of pyridine, 90mg of compound (14) were added to the solution, and the latter wasstirred for 1 day at room temperature. The working-up was effectedanalogously to Example (1f), the end product being purifiedchromatographically over 5 g of silica gel (system C).

Yield: 21 mg (23.6%); R_(f) value (system C): 0.34 (sisomicin: R_(f)value: 0.25).

EXAMPLE 61-N-(1,4-Dihydroxy-3-n-propylamino-but-2-yloxycarbonyl)-sisomicin (acompound (53a)) ##STR17##

(a) Preparation of compound (9a) (with Z=n--C₃ H₇)

5.76 g (0.04 mol) of 4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0]octane(compound (8)) (see J. Org. Chem. 41, 2469 [1976]) were heated underreflux in 20 ml of methylene chloride with 2.4 g of n-propylamine for 10hours, and the mixture was then concentrated in vacuo at 40° C.

Yield: 7.3 g of oil (90%); R_(f) value (system D): 0.33.

(b) Preparation of compound (10a)

A solution of 0.95 g of NPS-Cl in 2.5 ml of dioxan and 2.5 ml of 2 NNaOH were added simultaneously to a solution of 1 g of compound (9a)(0.005 mol) in 7 ml of dioxan at pH>8. The mixture was stirred for a fewhours at room temperature, and was concentrated in vacuo, taken up inmethylene chloride, washed with water, dried with Na₂ SO₄ andconcentrated by evaporation. It was purified by chromatography over 60 gof silica gel, using toluene as the eluant.

Yield: 1 g of orange oil, Rf value (system A): 0.4

(c) Preparation of compound (11a)

0.89 of compound (10a) (0.0025 mol) were reacted in 7.5 ml of pyridinewith 0.5 g of p-nitrophenyl chloroformate, and the reaction mixture wasworked up analogously to Example (1e).

Yield: 1.1 g (84%); Rf value (system A): 0.76; IR: 1,770/cm.

(d) Preparation of compound (53a)

A solution of 165 mg (1.5×10⁻⁴ mol) of3,2',6',3"-tetra-N-(o-nitrophenylsulphenyl)-sisomicin (30) in 0.75 ml ofpyridine were reacted with 90 mg of compound (11a), and the reactionmixture was worked up according to Example (1f). The cleavage of theisopropylidene protective group was quantitative after the acid aqueoussolution had been standing for 2 hours.

Yield: 20 mg (21%); Rf value (system C): 0.51 (sisomicin: 0.24).

EXAMPLE 7 1-N-(1,4-Dihydroxy-3-amino-but-2-yloxycarbonyl)-sisomicin (acompound (53b))

The preparation was effected according to Example 6, using NH₃, via thestages of compounds (9b) (Rf value [system D]=0.20), (10b) (Rf value[system A]: 0.20) and (11b) (Rf value [system A]=0.68; IR=1,780/cm) in ayield of 18%. Rf value (system C): 0.27 (sisomicin: 0.25).

EXAMPLE 81-N-(1,4-Dihydroxy-3-n-butylamino-but-2-yloxycarbonyl)-sisomicin (acompound (53c))

The preparation was effected according to Example 6, using n-butylamine,via the stages of compounds (9c) (Rf value [system D]: 0.57; meltingpoint 156°), (10c) (Rf value [system A]: 0.37) and (11c) (IR: 1,780/cm),in a yield of 30%; Rf value (system C): 0.54.

EXAMPLE 91-N-[1,4-Dihydroxy-3-(2-hydroxyethylamino)-but-2-yloxycarbonyl]-sisomicin(a compound (53e))

The preparation was effected according to Example 6, usingO-tritylethanolamine, via the stages of compounds (9d) (Rf value [systemD]: 0.7), (10d) (Rf value [system A]: 0.42) and (11d) (Rf value [systemA]: 0.92), to give the compound (53d), the O-trityl protective groupbeing split off in the last step, with the formation of the compound(53e), by leaving the acid aqueous solution to stand for 15 hours.

Yield: 49%, Rf value (system C): 0.38.

The present invention also comprises pharmaceutically acceptablebioprecursors of the active compounds of the present invention.

For the purposes of this specification the term `pharmaceuticallyacceptable bioprecursor` of an active compound of the invention means acompound having a structural formula different from the active compoundbut which nonetheless, upon administration to a warm-blooded animal isconverted in the patient's body to the active compound.

What is claimed is:
 1. A compound, which is1-N-([R,S,R,S]-6-Amino-2,3,4,5-tetrahydroxy-hexyloxy-carbonyl)-sisomicinor a salt thereof.
 2. A compound, which is1-N-(3-Amino-2,2-bis-[hydroxymethyl]-propyloxycarbonyl)-sisomicin or asalt thereof.